Remote inputs to IoTaWatt

I am about to set up an IoTaWatt which will be located at the main input/output of the property (garage). The solar inverter is also here so I will be able to easily log total imports, total exports and solar generation.

The house, and all its separate circuits, is over 20m away from this point. I am currently working to get the network with wifi coverage extended to the IoTaWatt location.

My challenge is to get separate circuit inputs (CTs) connected to the IoTaWatt. I would like to see individual contributions from at least the HWS and heat pump heater which are my biggest consumers. A separate IoTaWatt instance seems untidy but I am not seeing too many options.

Does anyone have any suggestions for using circuit level sensors in a different building?

Twenty meters is a long way. Separate units is one solution.

Extending with CAT6 wire is a possibility, although you would need to do some electrical work to adapt the 3.5mm jacks at each end. I think it would work OK, although I haven’t tried that length the math says it’s only 4 ohms so shouldn’t be a problem. It would also depend on what kind of conduit you have between the two. You should not run it through a high-voltage conduit.

The CAT6 has four twisted pairs, so you can extend four CTs with one run. I would recommend you put the IoTaWatt in the house and extend to the garage to pick up the inverter and any load center you may have in the garage.

I’m yet to dig the trench and run the network cabling but I had already decided to run an extra Cat6 cable (or perhaps two). 20m distance will quickly blow out to 30 once I thread it around walls and over roof trusses.
My preference is to commission the unit in the garage and then enhance its value with refined inputs when time and motivation permits. If I add inputs later, it will be building on an already stable system which should make troubleshooting so much easier.
If I commission it in the house, I need to have the complete solution including long CT runs before I see any data flowing.
I was really looking for the lazy option but I guess that nothing worthwhile comes cheap.

That should be fine. Install in the garage and move it later.

@Whatto: any feedback on how that worked out? I have a similar situation and wonder how Cat6 cable worked out for you.


Hi @jdubner Cat6 cable didn’t work out for me because I never even tried to use it. The unit sits in the shed (where the inverter is) and the house is still represented by only a single input.
One year on I am glad I didn’t try to rewire the property looking for data. Over time I have come to recognise the ‘signature’ of all the appliances I want to see in the single channel. High users are easy to see and also what I am interested in. That said, if I could ‘see’ more I’m sure I could use that intelligence too but I don’t miss what I never had.

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Thank you for following up with that report. And I hear you: “good enough is the enemy of perfect” or something such. I’d be satisfied with that setup too, looking for the ‘signature’ of major loads.

I guess my situation, while similar, is not identical. My remote circuit is my solar installation so I do want to include it but it’s connected to a remote panel that also feeds other loads. So instrumenting the feed from the main to the remote panel would include those loads as well as the solar generation.

Right now I’m running a homebrew Arduino/YHDC current probe on only the solar but would like to measure the mains too. I would also like to avoid a lot of work and expense .

It’s a long shot, but what kind of loads are there in the remote panel. Specifically, are they relatively small and are they all 120V?

Alas, there are all kinds of loads on the remote panel (with the solar feed): heavy 120V lighting loads, a furnace, and a 240V compressor. (It’s an aircraft hangar adjacent to my house.)

It was a long shot. My idea was that if you only had minimal 120V loads you could have put all of them on one leg. The other leg would then be representative of the solar when you “double”. The neutral would give you the sum of the 120V loads.